Mystical Serpent

Flying, bestow {4}{w}{u}
Mystical Serpent and enchanted creature have "Whenever this creature deals combat damage to
an opponent, you may draw a card".
Enchanted creature gets +3/+3 and flying.
Forecast—{1}{w}{u}, Reveal Mystical Dragon from
your hand: Reveal the top card of your library. If
it's blue, draw it.